In the manufacturing and processing of pharmaceutical tablets and the like, it is usually necessary to test such tablets for hardness. Such tests in the past have been carried out in apparatus utilizing springs or compressed air or, in some cases, an indicator is mechanically actuated in response to movement of a mechanical linkage having the test tablet interposed as one element in the linkage.
Problems inherent in these models include interference caused by tablet particles, calibration difficulties and inherent difficulties of reproducibility of test results.